This invention relates generally to conveyers and more particularly to a high precision feed chain for accurately guiding objects through various processing equipment.
Conveyer systems are used to transport different articles such as timber, consumer goods, and manufactured goods along a given path during different stages of processing. For example, conveyer systems move logs through different stages of edging and cutting that eventually form the log into a board.
Various monitoring and processing equipment, such as electronic vision recognition systems, are utilized in conjunction with the conveyer to analyze the shape, condition and position of articles as they travel on the conveyer. For example, vision recognition systems are used to identify knots and imperfections in raw lumber and, in addition, identify the position of the lumber in relation to the conveyer. The calculated position is then relayed to cutting and chipping machinery that cut the log into a desired shape.
Due to the timber shortage, it is highly desirable and cost effective to maximize the total amount of finished lumber capable of being extracted from each log. Thus, expensive laser system and vision recognition systems have been developed for use in conjunction with conveyer systems to increase the precision of cutting and other processing of raw timber.
While the electronic technology used for identifying and cutting lumber has significantly improved, the accuracy of the overall cutting process is still limited by the mechanical conveyer system used for transporting the lumber. For example, standard conveyer systems use a belt or chain system that supports and transports the timber while being processed. However, the belt or chain of a conveyer system, while moving in a semi-controlled longitudinal direction, can also move laterally back and forth and vertically up and down due to vibration, slippage, etc. When the conveyer moves in an uncontrolled lateral or horizontal direction, the reference point of the log in relation to the conveyer changes. If cutting or other processing equipment starts processing the object on the conveyer based on a previously defined reference point, the processing equipment will cut the log in the wrong location. For example, a chipper may cut too far into the side of a log, in turn, destroying usable portions of the log. In addition, if the log is moving due to conveyer vibration, the machinery will not cut the lumber smoothly, further degrading the quality of the finished lumber.
In addition to uncontrolled lateral movement, objects on conveyers change longitudinal position due to conveyer belt slippage and slippage between of the object and the top contact surface of the conveyer. Longitudinal slippage also causes the log to be cut at a different location than what was initially identified by the automated cutting equipment.
Accordingly, a need remains for a conveyer system that can hold and transport object in a highly stable precise manner for more accurate processing.